These are Rectify Series drop-in speaker system for Atlas Master QSI-era locomotives. More than just a box, the enclosures features Diapasonic Tuning™, which allows the lower frequencies to accurately develop and resonate, clears the midrange of excess resonance and tunes the upper-mid/high response.
 
Two versions are available. The ALMA-QSI1-RC1 is a half-round shaped system that fits within the a-frame speaker mount and fires down over the drive-shaft. These systems work in many of the Atlas QSI-era frames with the a-framed speakers. If your a-frame opening measures about 28mm in diamteter with at least 17mm of height between the apex and drive-shaft, these will work. No modifications are needed to install the speaker. Simply remove the stock speakers or cover-plates on non-sound units and use strips of double-sided mounting tape to secure the Scale Sound Systems speaker within the frame.
 
The ALMA-QSI2-RC1 is a larger system designed to replace the a-frame speaker mount. I have used these in GP38/40's. The system features a mounting hole on the rear-side to reattched the stock lighting PCB should you so desire. No modifications are needed to replace the factory speakers. Simply remove the two screws holding the stock speaker housing to the frame, remove the rear headlight PCB from the speaker housing, install the SSS system with a touch of adhesive, screw the rear headlight PCB onto the SSS system and conect the speaker.
 
The speakers come fully assembled and tested.
 
Dimensions are:
QSI1: 16mmH x 18mmW x 27mm Dia.
QSI2: 30mmH x 18mmW x 33mmL